| Objectives:The sterilizing effect of hydrogen peroxide gas plasma sterilizer was observed under the condition of laboratory, including its conditions and parameters. Through field investigation in the hospital, know the general situation of hydrogen peroxide gas plasma sterilizer. In addition, provide laboratory base for proper using the sterilizer in the hospitial and technical information for developing health standards of the sterilizer.Methods:1. At the present stage, using situation of hydrogen peroxide gas plasma sterilizer in hospital include major categories of sterilization items, loading situations, lumen type apparatus kinds, cleaning and drying of the materials before sterilization as well as monitoring of cleaning materials.2. Sterilization of the sensitivity of the determination of the medium. The suspension of Bacillus stearothermophilus and Bacillus subtilis suspension was serially diluted with water and then were inoculated with sterilized bromocresol purple peptone and TSB, in accordance with the requirements of training and observations.3. Compare the sterilization effect of hydrogen peroxide gas diffusion and plasma. For hydrogen peroxide diffusion, reaction time were 6s,18s,30s,42s and 1 min, concentration were 2.5mg/L and 5mg/L, operating temperature was 50℃. For the plasma process, reaction time were 5min,10min and 15min, operating temperature was 50℃.4. The influence of temperature on the sterilization effect under corresponding pressure. PSR-100 hydrogen peroxide plasma sterilization resistance apparatus was taken to tesing the Bacillus stearothermophilus, reaction time were lmin,2min, 3min and 5min, concentration was 2.5mg/L, operating temperature was 25℃. 5. The influence of using hydrogen peroxide concentration on the results of penetrating sterilization. Comparing sterilization effect before and after purification of supplemental hydrogen peroxide.6. The influence of plasma discharge on the temperature through placing the temperature and pressure data loggers in different instruments, including Johnson sterilizer, Baixiang sterilizer, Yilu sterilizer and biological indicator evaluator resistometer of hydrogen peroxide gas.7. The influence of humidity on the sterilization effect of hydrogen peroxide gas plasma sterilizer.100NX Johnson sterilizer was taken to disinfect wet and dry lumen, following aseptic monitoring and quantitative culture of lumen in order to compare the impact of humidity.8. The influence of organic matter on the sterilization effect of hydrogen peroxide gas plasma sterilizer.50% and 25% calf serum,25%,12% and 6% BSA solution were taken respectively to contaminate bacterial slide and compared surface and internal lumen sterilization.9. The influence of sodium chloride on the sterilization effect of hydrogen peroxide gas plasma sterilizer.200%,100% and 50% physiological saline were taken respectively to contaminate bacterial slide and compared surface and internal lumen sterilization.10. The influence of blood on the sterilization effect of hydrogen peroxide gas plasma sterilizer.10% and 1% goat blood, diluted with deionized water, were taken respectively to contaminate bacterial slide and compared surface and internal lumen sterilization.11. The influence of different materials lumen on the sterilization effect of hydrogen peroxide gas plasma sterilizer. Different brands of plasma sterilization were taken to sterilize stainless steel lumen and polyfluortetraethylene lumen. Inner diameter of inner diameter was 1mm, length were 500mm and 600mm. For polyfluortetraethylene lumen, inner diameter was 1mm, length was 2000mm.Results:1. Materials that can be sterilized by the hydrogen peroxide gas plasma sterilizer includes:thoracoscope, laparoscope, surgical drills and batteries, electric knife lines, micro-power motors, electrocautery blade, three-way hammerhead, laser desensitization fiber head, laryngoscope, fiber cable, silicone tube, conchoscope, shadowless lamp lights, lmm of minimum diameter of sterile lumen type equipment, 1500mm of maximum length of sterile lumen type equipment, sterilization load accouting for 60% of sterilization cabin. Most equipment can be cleaned using multienzyme lotion and dried. Using naked eye to detect the cleaning effect.2. Inoculated 10-100cfu of Bacillus stearothermophilus at the sterilized bromocresol purple peptone. After 24 hours, bromocresol purple peptone totally discolour. Inoculated 10-100cfu of Bacillus subtilis in the TSB, After 48 hours, mycoderma appeared in the TSB.3. Taking Johnson Bacillus stearothermophilus slide as testing materilas.2.5mg/L of hydrogen peroxide at a temperature of 50℃, achieving the requirements of sterilization needed 42S.5mg/L of hydrogen peroxide at a temperature of 50℃, achieving the requirements of sterilization only needed 6S. At a temperature of 50℃and plasma discharge for 5min, 10min and 15min, logarithm of sterilization is less than 2.4. Taking Johnson Bacillus stearothermophilus slide as testing materilas. Under the condition of 20℃of operating temperature,2.5mg/L of hydrogen peroxide concentration L, lmin,2min, and 3min of reaction time, there were the growth of bacteria. Under the condition of 50℃of operating temperature,2.5mg/L of hydrogen peroxide concentration, lmin of reaction time, Bacillus stearothermophilus were totally killed.5. Under the same sterilization circumstances, hydrogen peroxide gas plasma sterilizer without equipped pure hydrogen peroxide system of different manufacturers including Shanyuan CDMJ-100, Baixiang and Xinhua have failed to disinfect stainless steel lumen with internal diameter of 1mm, length of 500mm, but these sterilizers equipped pure hydrogen peroxide system had effective sterilizing on these stainless steel lumen.6. Through testing temperature variation in the pre-plasma of hydrogen peroxide gas plasma sterilizer of different manufacturers, after about 10min of plasma discharge, the temperature can rise to above 50℃, which indicated plasma discharge had obvious effects on the rise of temperature.7. In the same sterilization cycle, the lumen sterilization treatment without humidification was qualified, while it failed to sterilization with humidification. After dring wetting lumen at 54℃in the oven for 30min, it still can not meet asepsis requirements. After drying wetting lumen using air gun for 15s, only a few reach sterilization requirements, but the sterilization effect is much better than the oven drying.8. Placing bacterial slide contaminated with calf serum and BSA on the surface had no significant effect on the sterilization, but placing in hard place of lumen, it failed to sterilization, while placing bacterial slide without contaminated calf serum and BSA in hard place of lumen, it can be sterilized.9. Placing bacterial slide contaminated with physiological saline on the surface had no significant effect on the sterilization, but placing in hard place of lumen, it failed to sterilization, while placing bacterial slide without contaminated physiological saline in hard place of lumen, it can be sterilized.10. Placing bacterial slide contaminated with goat blood on the surface had no significant effect on the sterilization, but placing in hard place of lumen, it failed to sterilization, while placing bacterial slide without contaminated goat blood in hard place of lumen, it can be sterilized.1% of goat blood have obvious effects on the sterilization. 11. Hydrogen peroxide gas plasma sterilizer of different manufacturers including STERRAD 100S, Shanyuan CDMJ-100, Kaisipu casp-50, Baixiang PS120, Yilu ETP-100, and Laoken (?) LK/MJG-100 disinfected stainless steel lumen with internal diameter of lmm, length of 500mm and polyfluortetraethylene lumen with internal diameter of lmm, length of 600mm. To stainless steel lumen with internal diameter of 1mm, length of 600mm, there appeared sterilization failure phenomenon.Conclusions:1. Internal diameter and length of lumen type devices are within the scope approved by the Ministry of Health. Most hospitals have excessive loading capacity, basically meeting the cleaning requirements, lacking of monitoring of surface cleaning of lumen type devices.2. Bromocresol purple peptone and TSB meet requirements of ISO11138-1 7.2.1. In the case of inoculated colonies no more than 100CFU, medium appears color changes or mycoderma.3. Vaporation and diffusion of hydrogen peroxide can kill the spores within very short time. With the concentration of hydrogen peroxide increasing, killing time reduces. Plasma discharge has certain effects on killing the spores, but it needs relatively long time. Therefore, the dominating role of hydrogen peroxide gas plasma sterilizer is hydrogen peroxide.4. As the temperature increasing, time of hydrogen peroxide killing spores will reduce in the sterilizer. This is because the boiling point of hydrogen peroxide is different in different pressure. Under the pressure of the sterilization cabin, generally between 1000pa and 2000pa, the boiling point of hydrogen peroxide is above 50℃.5. To the same brand machine, compared with sterilizer without equipped pure hydrogen peroxide, sterilizer equipped pure hydrogen peroxide system has effective sterilization of stainless steel lumen with internal diameter of lmm, length of 500mm. So with increasing concentration of hydrogen peroxide, the impact on the sterilization effect of lumen type devices becomes greater.6. Plasma stage has obvious warming effects on materials in the sterilization cabin. During the pre-plasma of lOmin or so, temperature of temperature probe can be above 50℃.7. Humidity affects the sterilizing effect of hydrogen peroxide gas plasma sterilizer on the lumen equipments. Lumen with humidification can not reach the sterilization requirements, but the lumen without humidification can be sterilized. After drying the wetting lumen at 54℃in the oven for 30min, it also fail to disinfect. Sterilization after drying lumen using air gun for 15s is alse failed.8. Calf serum and BSA affect sterilization of hydrogen peroxide gas plasma sterilizer to lumen type device. With increasing concentration of calf serum and BSA, the impact on the sterilization effect becomes greater.9. Physiological saline affects sterilization of hydrogen peroxide gas plasma sterilizer to lumen type device. With increasing concentration of physiological saline, the impact on the sterilization effect becomes greater.10.1% goat blood affects sterilization of hydrogen peroxide gas plasma sterilizer to lumen type device. With increasing concentration of goat blood, the impact on the sterilization effect becomes greater.11. To the sterilization of lumen type devices, sterilizing time of polyfluortetraethylene lumen is more than stainless steel lumen in the same inner diameter. So different materials affect the sterilization effect of hydrogen peroxide gas plasma sterilizer.
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